we get the story tonight from nbc's jim miklaszewski. >> reporter: as a navy s.e.a.l. sniper in iraq, chris kyle was so feared, the enemy called him the devil of ramadi and put an $80,000 on his head. >> it gave me pride knowing i put fear in the mind of the terrorists and made them fearful of me. >> tragically, it was back home where kyle and a friend were shot and killed. the suspect is a 25-year-old marine reservist, eddie ray routh. without warning, routh allegedly shot the two victims with a semiautomatic handgun. he's in custody facing two charges of capital murder. sheriff tommy bryant told reporters, routh turned on his guards overnight. >> he became aggressive, and they believed he was about to assault them so they tased him and after they tased him, they put him in a restraint. >> reporter: routh served two tours in iraq. once back home, his family reportedly feared he was suffering ptsd, post traumatic stress, and asked chris kyle for help. >> some people are definitely coming back with ptsd. and i want to try to figure out everything i can do, possibly, to